1. Field of the Invention
The field of this invention is portable routers.
2. Description of Related Art
Portable routers for shaping and cutting wood, plastic and other building materials are known. These tools typically have a motor unit with an AC electrical motor activated by an on/off switch. An output shaft extends from one end of the motor unit and is fitted with a collet chuck and a collet fur holding a router hit or other cutting tool. An adjustable base fits around the exterior profile of the motor unit. The axial position of the base relative to the motor unit can be adjusted through a rack and pinion or threaded arrangement disposed between the base and the motor unit. An electrical power cord extends from the motor unit to provide electrical power to the AC motor from an external power outlet. Other variations of this basic router exist and include the plunge router and the D-handle router.
All of the above described routers suffer from one common drawbackxe2x80x94they each require an external power source and a power cord. So-called cordless power tools having a detachable battery have been produced in the form of drills, screwdrivers, saws, etc. Although several cordless routers or similar cordless tools have been proposed, e.g., in U.S. Pat. No. 6,050,759 to Bone, U.S. Pat. No. 5,902,080 to Kopras, U.S. Pat. No. 5,451,123 to Fertitta, Jr., and U.S. Pat. No. 5,298,821 to Michel, none of these proposed tools provides all of the advantageous features which are found in the cordless router of the present invention. For example, the tools proposed in these patents are not powerful enough to perform the most common router operations. The prior art patent to Michel, for example, describes the voltage of the tool proposed therein to be a maximum of 4.8V. The patent to Kopras discloses a tool with an AC electric motor adapted for 115-120V to be powered by a detachable battery. But it is completely unclear in Kopras how the detachable battery of that proposed tool would provide 115V AC.
Also, the placement of the detachable batteries on the tools proposed in these patents is not in the most advantageous position. The batteries in the prior art patents to Kopras, Fertitta Jr., and Michel attach to the tools disclosed therein by movement in a direction parallel to the longitudinal axis of the tool. Thus, if those tools were lifted longitudinally by grasping only the battery, the locking mechanism would necessarily bear the weight of the router. If the locking mechanism were to fail or were accidentally released, the tool would be dropped. The prior art patent to Bone suggests batteries which slide into the tool at an angle other than parallel to the longitudinal axis of the tool, but then the tool is not at all balanced over the output shaft.
The tools proposed in these patents also suffer from other drawbacks.
According to the invention, a cordless router may have a housing, a battery releasably attached to the housing, a locking mechanism provided on the housing for releasably retaining the battery in a locked position relative to the housing, a DC motor positioned inside the housing having a rotational axis and powered by the battery, and an output shaft powered by and extending from the DC motor having on the end thereof a tool clamping device for holding a cutting tool. The battery slides into the locked position relative to the housing in a direction substantially normal to the rotational axis. When the battery is in the locked position relative to the housing, the center of gravity of the cordless router motor unit is substantially colinear with the rotational axis of the output shaft.
According to the invention, a cordless router may also have a housing, a battery releasably attached to the housing providing a minimum voltage of at least 18V, a DC motor positioned inside the housing and powered by the battery, the DC motor having a maximum power output of at least ⅝ hp. when powered by the battery. The cordless router may also have a power switch electrically connected to the battery and electrically connected to the DC motor for turning the motor on and off, and an output shaft powered by and extending from the DC motor having on the end thereof a tool clamping device for holding a cutting tool.
According to the invention, a cordless router may also have a housing comprising a metal barrel and a plastic battery housing joined to the metal barrel with fasteners. A DC motor is disposed at least partially inside of the metal barrel and an output shaft is powered by and extends from the DC motor. The output shaft has on the end thereof a tool clamping device for holding a cutting tool. A battery is detachably mounted to the battery housing for powering the DC motor.
Also according to the invention, a cordless router may have a housing, a DC motor positioned inside the housing, a battery releasably attached to the housing so that the rotational axis of the DC motor is on a line passing through the battery, the battery powering the DC motor, an output shaft powered by and extending from the DC motor having on the end thereof a tool clamping device for holding a cutting tool, and a power switch disposed at least partially inside of the housing and having a button extending out of the housing, the power switch being radially spaced from the DC motor and positioned below the battery, the power switch controlling the passage of electrical current from the battery to the DC motor.
Also according to the invention, a cordless router may have a housing, a battery releasably attached to the housing, a DC motor powered by the battery and positioned inside the housing, and an output shaft powered by and extending from the DC motor, with the output shaft having on one end thereof a collet chuck adapted to hold router bits having a shaft diameter of at least approximately xc2xdxe2x80x3.
Also according to the invention, a router set may include a cordless router motor unit, a corded router motor unit, and a base. The cordless router motor unit may have a housing having a barrel with an external profile, a battery releasably attached to the housing, a DC motor supported inside the housing and powered by the battery, and an output shaft powered by and extending from the DC motor having on the end thereof a tool clamping device for holding a cutting tool. The corded router motor unit may have a housing having a barrel with an external profile, an AC motor supported inside the housing, a power cord electrically connected to the AC motor and extending from the housing for bringing electrical power from an external electrical source to power the AC motor, and an output shaft powered by and extending from the AC motor having on the end thereof a tool clamping device for holding a cutting tool. The base may have an internal surface substantially corresponding to the external profile of the barrel of the cordless router motor unit and the external profile of the barrel of the corded router motor unit, and be capable of engaging the barrel of the cordless router motor unit and moving axially thereon and also capable of engaging the barrel of the corded router motor unit and moving axially thereon.